# The impulse response graph suddenly jumps in the second period

**URL:** <https://forum.dynare.org/t/the-impulse-response-graph-suddenly-jumps-in-the-second-period/27903>\
**Category:** Stochastic simulations\
**Created:** [18 August 2025 17:31 UTC](https://forum.dynare.org/t/the-impulse-response-graph-suddenly-jumps-in-the-second-period/27903 "2025-08-18T17:31:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![JimsVims](https://forum.dynare.org/letter_avatar_proxy/v4/letter/j/c77e96/32.png) [@JimsVims](https://forum.dynare.org/u/JimsVims)\
**Post date:** [18 August 2025 17:31 UTC](https://forum.dynare.org/t/the-impulse-response-graph-suddenly-jumps-in-the-second-period/27903/1 "2025-08-18T17:31:28Z")

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Hi everyone, I would like to ask why my impulse response graphs look strange. Almost every graph has a jump in the second period.  
Thanks！

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**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\
**Post date:** [19 August 2025 08:08 UTC](https://forum.dynare.org/t/the-impulse-response-graph-suddenly-jumps-in-the-second-period/27903/2 "2025-08-19T08:08:43Z")

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Sometimes it is a timing error, sometimes an economic feature of the model. Without more details and/or codes it is impossible to tell.

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**Author:** ![JimsVims](https://forum.dynare.org/letter_avatar_proxy/v4/letter/j/c77e96/32.png) [@JimsVims](https://forum.dynare.org/u/JimsVims)\
**Post date:** [19 August 2025 15:52 UTC](https://forum.dynare.org/t/the-impulse-response-graph-suddenly-jumps-in-the-second-period/27903/3 "2025-08-19T15:52:38Z")

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Thank you very much, Professor Pfeifer.  
I added consumption habits and investment adjustment costs and found that the graph became smoother. Is this in compliance with the standard?

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**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\
**Post date:** [20 August 2025 11:27 UTC](https://forum.dynare.org/t/the-impulse-response-graph-suddenly-jumps-in-the-second-period/27903/4 "2025-08-20T11:27:29Z")

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If you can exclude that there is another error hidden in the file, this suggests it is about endogenous propagation. In that case, adding features like habits and adjustments costs should indeed solve the issue.